Figure 7.

Statistical properties of the IBI time series generated by the mathematical model. The left columns (a, c, e, and g) represent the results obtained by setting μ = 0.0182. The right columns (b, d, f, and h) display the results obtained by setting μ = 0.01. (a and b) Raster plots of a portion of the time series. (c and d) Time series of the beat rate (number of beats per minute). (e and f) Histograms of the IBIs. (g and h) Detrended fluctuation analysis. The meanings of the symbols are the same as those in Fig. 3. The error bars in panels g and h represent the root mean-square deviations calculated from 20 independent runs. The solid lines are the least-squares fits to the original data in the range [10^2.5, 10^4.5] in g and [10^3.2, 10^4.5] in h, respectively. The scaling exponents α in these regions are 0.85 ± 0.01 in g and 0.75 ± 0.01 in h, respectively.